OnStar – best known for connecting drivers to live operators who provide directions or summon emergency help after an accident – will start using AT&T in its 2015 models, which go on sale in mid-2014. – best known for connecting drivers to live operators who provide directions or summon emergency help after an accident – will start using AT&T in its 2015 models, which go on sale in mid-2014.

GM said that Verizon Wireless, which has been the company’s wireless provider since 1996, would still support OnStar services for all existing GM vehicles and any new models that come out before the 2015 models are launched.

Verizon currently has superior LTE coverage (273.5 million people versus 170 million for AT&T today), but AT&T’s promises to cover 300 million US consumers by year end 2014.

AT&T and GM plan to develop some apps together, as well as allow outside software developers to contribute.

The companies have not determined how much the service will cost, but Glenn Lurie, AT&T’s president of emerging enterprises, said adding a wireless connection inside cars would open doors to a wave of new apps that make vehicles smarter.

“The car is going to be a smartphone with four wheels,” Mr. Lurie said in an interview. “The opportunities are endless when you think about adding an LTE pipe to a car.” He said potential apps might display real-time traffic on a map or perform enhanced vehicle diagnostics, giving consumers a deeper understanding of what is happening inside their cars. Children sitting in the back seat might be able to stream Netflix over the wireless connection.

Lurie said he believed the connected car would be AT&T’s “next billion dollar business.”